A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering of the Asian Institute of Technology, Bangkok, Thailand

Thesis (M.Eng) - Asian Institute of Technology, 1976

Granite residual soil formations in Northern Thailand were investigated with respect to their mineralogical, chemical, physical properties and how these are affected by the degree of weathering. Field tests included field density, cone penetration, Schmidt hammer, and direct shear measurements while laboratory investigations comprised mineralogical and chemical analyses as well as studies on index properties and their response to different pretreatments. The results showed that the mineralogical, chemical, physical and strength properties at any point of the deposit depended on the degree of weathering. Oven drying reduced the liquid and plastic limit but had little effect on grain size distribution. Greater effects of pretreatments were noticed for samples containing montmorillonite as compared to those containing illite or kaolinite. In Casagrande's plasticity chart, the presence of organic matter, iron oxides and kaolinite pulled the points below the A-line while the presence of montmorillonite and illite moved the points above the A-line. Decreasing clay content and oven drying moved the points down along the A-line. An attempt was made to subdivide the profile studied into zones of weathering following proposals of previous investigators.